受控组件

class NameForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: ''};

    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }

  handleChange(event) {
    const inputValue = event.target.value.replace(/\s/g,'');
    let str1 = inputValue.substring(0,3);
    let str2 = inputValue.substring(3,7);
    let str3 = inputValue.substring(7,11);
     str2 ?str2 =" "+ str2:null;
     str3 ?str3 =" "+ str3:null;
    this.setState({value: str1+str2+str3});
  }

  handleSubmit(event) {
    alert('A name was submitted: ' + this.state.value);
    event.preventDefault();
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Name:
          <input type="text" value={this.state.value} onChange={this.handleChange} />
        </label>
        <input type="submit" value="Submit" />
      </form>
    );
  }
}

ReactDOM.render(
  <NameForm />,
  document.getElementById('root')
);